GeAmp1W MicroCombo

The GeAmp1W MicroCombo is a real micro-amp for harp or guitar, not a rebadged asian gadget.
Its accurate electronics, the vintage speaker and its solid cherrywood case give it a great musicality.
It will let you play for the pleasure or rehear at home, with a sound that even neighbors will appreciate !

MicroCombo 1W by - Logo

MicroCombo GeAmp1W - Ampli germanium, HP NOS, boîtier merisier

The MicroCombo 1W, basic version

Some electronic circuits have known a moment of grace, then have been forgotten in favor of  technologies more profitable for industry…
Sometime they can become fashionable again: Thus the 5-watt tube amps currently trendy are never more than clones of the low frequency stage in radios from the years 1940-1950… I know : I transformed lots of them when I was sixteen!

It’s the same in transistor amplification: some radios in the 65/75 years had very musical amplifiers, with a welcome efficiency and able of a warm saturation. Well here they are again, redeveloped for guitar and harp by Guitar Poppa …

Main features

Dimensions : front 7.5×6 inch, depth 4 inch.
Solid cherrywood enclosure, warming the sound.
Germanium 1W power amp, 60s technology soft clipping…
4 inch NOS, high efficiency speaker.
Low noise silicon preamp, original Tone Control.
3 voicings, adjustable phone outpout, and line output for external amp or recording (*** option).
Sold with a grounded 12V power supply.

listen to samples…

download the leaflet

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Controls and connectivity

MicroCombo GeAmp1W - commandes et connextivité

Control panel of the MicroCombo GeAmp1W, *** version .

*** Version , from left to right :
Input Jack, switching the battery.
Presets switch. Normal / Fat / Sharp.
Tone control. Neutral at 12:00 ; warm to the left ; fenderish to the right.
Volume control. Full clean level around 12:00.
Led power On indicator
Trimmer for phone level setting.
3.5mm phone jack.
3.5 or 6.35mm line output jack (50 to 250mV according to the volume control).
Coaxial power jack, 2.1mm diameter, center negative.

The basic version only includes input jack, tone, volume, led, and power DC jack.

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MicroCombo GeAmp1W works with 7.5 to 12V, and consumes 0.3 to 0.8A.

Internal power supply : 6 AA batteries. Coupler at the rear of the enclosure.
• Autonomy : 2 to 5h according to the dissipated power.
• Power on through the input jack.
External power supply : 7.5 à 12V : 2.1mm coax sockett, center negative.
• With 9V : 0,8W nominal power. Organic overdrive above this level.
• With 7,5V : power is limited, sound gets easily dirty… Good for a Lo-Fi feel!
• With 12V : 1,3W of clean sound before overdrive. Good when higher dynamic is needed.

New and interesting (2019) :
• A 12V 3A rugged power supply, with grounding, is supplied in each version.
• It ensures optimum power, without hum or electrostatic noise.

Back view, battery coupler open.

Reliable industrial power supply, modified by Guitar Poppa.
Standard connectivity, grounding eliminating noise.

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To order

1. Choose the version.
2. Specify the options.
3. Specify the shipping zone.
4. Click <Add to cart>.
5. Click ‘Cart’ on main menu, or keep on visiting.

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MicroCombo 1W
basic version

Perfect for roots harp and guitar

• Basic electronics, volume and tone controls.
• Siare 4″ speaker, alnico magnet.
• No preset switch, no phone output, no line output.
• Powered by 6 AA batteries, or a grounded 12V-3A power supply (supplied).

• Select the input sensitivity by clicking below on the desired option.
(detailed informations at the bottom of this page …)

MicroCombo GeAmp1W, version basic

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MicroCombo GeAmp1W - version ***MicroCombo 1W
*** version

Electronics and powering of the basic version, with useful additional functions

• 3 voicings : Normal / Fat / Sharp
• Phone output 3.5mm jack, with speaker disconnection and volume adjust.
• Line output 3.5 or 6.35mm jack, transmitting the sound texture of the final amp

• Select the input sensitivity by clicking below on the desired option.
• Select the speaker model by clicking below on the desired option.
• Select the diameter and the location of the line output sockett (click below …).
(detailed informations at the bottom of this page …)

MicroCombo GeAmp1W, version basic

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For those who wants more details

Close up on the preamplifier.

Input level option (in each version)

In order to better adapt the preamp to your favorite audio source, don’t forget to click on the desired option …

Guitar pick up (50mV on 600kΩ)
That configuration is suitable for almost any source, except piezo or ceramic bullet pickups for harp (like the Shure Green Bullet), which may overly distort the preamp …

Antique piezo or ceramic Harp mikes, like the Shure Green Bullet (150mV)
These piezo pickups can be violent because of their output level and their strong mediums. With this option, they will be well received and their bandwidth a little rebalanced.

Contemporary dynamic microphone, like the Shure SM57 (10mV)
High gain option. It can accommodate low level microphones with a sufficient range of gain, from clean sound to saturation.
Guitars with a low level output will also be better handled.

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NOS speakers (in each version)

Two 4 inch models by two major French manufacturers of the 60-70s …
They feature generous magnets and elaborate membranes : these  little speakers give a strong but not harsh sound.

Siare speakers with alnico magnet (a well known french brand in the 60-80s)
Installed originally in basic version, and available as an option in *** version .
Haut-parleur NOS Siare 10cm, aimant Alnico, fin 70s

• Perfect for harp and guitar played in roots style…
• The alnico magnet guarantees well pitched but sweet treble.
• It brings a typical compression when level is pushed …
• The spheric shape of the membrane brings a naturally dense tone.

Vega speaker, custom model for the french national radio (1961).
Available as an option in *** version.
Haut-parleur NOS Véga 10cm, aimant ferrite, 1961
• More jumpy than the Siare model. It is perfect to push the instrument forward.
• High efficiency and fast attacks due to a large ferrite magnet.
• Ribs on the membrane avoid deformations, which maintains clarity at any levels.
• Granulations avoid a nazillarde over-coloring, known as “cardboard sound” …

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3 voicings (*** option)

A switch lets select 3 typical voicings…

“Normal” (center)
• Neutral effect when the tone potentiometer is set at 12:00.
• To the left : Dimed treble, warmed tonality in the medium range.
• To the right : Brighter treble and notched low mids like in Fender amps.
• Low frequencies are boosted between 80 and 200Hz.
• This corrects the low volume of the enclosure, fattens the tone, and can bring a lo-fi dirt.
• Good to make the harmonica chubby and give some thigh to thin guitars.
• High medium and treble are boosted above 2kHz.
• The effect is that of a vintage treble booster, with sharp attacks in the English style.
• Keeps a clear sound when MicroCombo 1W *** is plugged into a 10 or 12 inch cabinet.

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Line Output (*** version)

It features a speaker simulator, to maintain a credible color to the exported sound..
• The signal is taken from the speaker output and transmits its texture and dynamics.
• Simple attenuation above 5 KHz and discrete hump towards 2.5kHz, to approach the spectrum of a guitar speaker without excessive phase shifts.
• Standard output level, low impedance : 50 to 250mV depending on volume setting. .

Dimensions and format of line output jacks: two clickable options
• 3.5mm jack socket on the upper front of the case.
• 6.35mm jack socket at the rear of the enclosure.

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